Switch casing



June ue., 1940. B R POND 2,204,695

SWITCH CASING Filed latch 17, 1938 2 Sheets-Sheet 1 l au@ FigJI Snventor Berram Gttorneg B. P. POND SWITCH CAS ING June 18, 1940.

Filed latch y 17, 1938 2 Sheets-Sheet 2 nventor Cttomeg ez'IramB Pond /fy/wv LA PatentedV June 18, 1940 UNITED STATES PATENT OFFICE 2,204,695 swrrcn cAsrNa Bertram P. Pond, Minneapolis, Minn., assignor to'Mlnneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation o! Delaware Application Mai-cn 17, 193s, serial No. 196,392

"11 claims. (ci zoo- 137) Figure 9 is a detail view of the extensions on This invention relates generally toaswitch casing and more particularly to a casing for a 'thermostatically operated switch and means for mounting thereon an insulated'panel for termii. nal connections, and a cover for the switch casing.

One of the objects ci this invention is to provide a switch casing which is simple in construction, cheap to manufacture, yet which is sturdy and eicient in operation.

switch.

Another object is to provide an insulated panel on the front side of which are mounted a series of electrical terminals and on the reverse side of which are mounted a plurality of open contact switches. It is contemplated that this unit shall be supported by the sides oi' the switch casing and positioned so as to be operated by a thermostat.

5 Still another object oi the invention is to provide a thermostatic switch having a cover for the switch casing which is held on at one end by means of the scale plate and an adjusting arm for the thermostat being inserted through a slot D in the Ycover and the other end oi which is held on by a`- releasable latch which engages in a hole in one side of the switch casing.

These and other objects will readily become 'apparent as the following specification is read in 5 the light oi' the accompanying drawings in which:

Figure 1 is a front view of the device with the cover on;

Figure 2 is a side view oi the device with the cover on, the releasable latch being shown in dotted lines;

Figure 3 shows the switch casing in its developed form;

Figure 4 is a front elevation of one type oi switch which may be mtunted in the switchv casing;

I Figure 5 is a side view of the switch shown in Figure 4, part being shown in section, taken on f the line 5 5 of Figure 4;

Figure 6 is a detail view oi one of the corners oi the switch casing looking toward the back;

Figure 'l is a section taken on the line 'I-I of Figure 6;

Figure 8 is a top view of the switch casing, the cover and part oifthe casing being shown in secz tion;

the insulated panel;

Figure is a front elevation oi an open contact type oi switch which may be carried on a panel and mounted on the sides of the switch casing, and

Figure llis a view showing the reverse side of the panel shown in Figure 9. I

Like reference numerals are used to designate like parts throughout the several views of the drawings.

Referring first to Figure 3, it will be seen that the switch casing II is shown in its developed form just as it is stamped out of a piece'of sheet metal and comprises aback I2, a top I3, a bottom Il and sides I5. The corners I6 of the back I2 are shown as rounded and in forming the casing the top, bottom, and two sides are bent upwardly and then their ends are bent to conform to the rounded corners I6. When this has been done, the ends of the sides will be adjacent;- the ends of the top and bottom as shown, for example, in Figure 4, and in order to make sure that there is no opening between the rounded corners I6 and the sides of the casing the corners are bent up asvshown at I1 in Figure 7.

It will be seen also in Figure 3 that notches I8 have been cut in the two sides of the casing, and in the right-hand side there is cut a hole I9 which, as-will be explained later, cooperates with a latch on the cover for the casing. The bottom I4 has an extension 20 in which is located a hole 2| for the purpose oi accommodating the lead wires for the switch mounted on the casing. In the top are cut two slots 22 for the purpose of supporting a scale which will -be described later.

Two hook members 23 and 2l are stamped out of the back I2 and are bent inwardly when the casing is iormedleaving holes 23 and 26 in back of the casing. The back I2 has a depressed portion 21 in the center oi which is located a round hole 23 about which are located a series of small arcuate slots 2l.

Referring now to Figure 5, it will be seen,that a sleeve 30 is provided with a series oi' small extensions 3I which are inserted through the slots 23 and bent over to form a permanent connection between the sleeve 33 and the back of the casing II. Inserted through the hole 23 is a tube 32 which is supported at one end by the sleeve 30 and which has -at that end two ears 33 and 34. VThe ear 33 supportsby means of screw 35 a bimetallic spiral 33 which is connected at its other end by a screw 31 toone end oi a torsion rod 38, the other end of which rotates freely in' a shouldered bearing 39 located within the casing I2. The ear 34 of tube 32 is bent inwardly and is provided with a hole through which the torsion f rod 38 passes so that the ear 34 forms a bearing for the rod. A circular plate 40 within the casing is provided with a series of holes through which projections 4I on the tube 32 are inserted and bent over or staked to form a permanentconnection. The bearing member 39 is fixedly connected to the circular plate 40. A cover plate 42 is mounted over the tube 32 and is provided with two holes through which the hook members 23, 24 are inserted so that plate 42 lies against the back plate I2 and covers the holes 25 and 26 left by the hook members 23 and 24. A friction washer 43 is placed around the tube 32 between the cover plate 42 and the circular plate 40 so that when the two plates are pressed together a certain amount of friction will oppose their relative movements. A resilient latch 44 seats on a shoulder on the bearing member 39 and the two reduced ends 46 and 41 engage beneath the hook members 23 and 24 in such a way that the latch 44 exerts a force tending to move the bearing member 39 tothe right as viewed in Figure 5 thereby holding the two plates 40 and 42 against the back plate I2, which will also maintain the tube 32 and hence the thermostat 36 and rod 38 in the position shown in Figure 5. Adjustably positioned on the end of rod 3B within the casing I I by means of screw 48 is a mounting member 49 which carries switch clip 50 in which is mounted a mercury switch 5|.

The circular plate 40 has connected thereto an offsetextension 52 which has therein a slot 53. A Z-shaped indicating arm 54 has one leg which lies against the extension 52, said leg having a reduced end 55 which is inserted in the slot 53. A screw 56 is inserted in a threaded hole in this leg and extends through an arcuate slot 51 in the extension 52. By loosening screw 56 the indicating arm 54 may be rotatably adjusted with respect to the extension 52 to afford a factory calibration for the switch. It will be noted that as the indicating arm 54 is mo'ved back and forth, it carries with it the circular plate 40 which causes rotation of the tube 32 and hence the thermostat 36. rod 38 and the mercury switch 5I. This provides the main adjustment for the switch.

A scale plate 58 is provided with two legs 59 which have extensions 60 that are inserted through the holes 22 in the top of the casing and are bent over to form a permanent connection to support the scale plate. This scale plate is provided with a slot 6I, see Figure 8. through which one leg of the Z-shaned indicating arm 54 is inserted. This cooperates with indicia 62 located on the face of the scale plate 58. 1n this manner the temperature for which the thermostatic switch is adjusted by thearm 54 may be directly read from the scale plate. An insulated panel 53 is provided for the purpose of carrying terminals 64 for the conductors 65 leading to the mercury switch and for terminals 66 which may be connected to conductors leading to an outside circuit which is to be controlled byr the switch. Referring to Figure 3, it will be noted that each of the notches I8 cut in the sides of the casing for the purpose of supporting the panel has an overhanging lip 68. rIhe panel 63 is provided with four extensions 51, two of which are shown in detail in Figure 9. Each extension 61 has a. reduced end portion 69 which is of a width sufiicient to pass between the sides of the notch be neaththe lip. The panel 53 has a length including the extensions 51 substantially equal to the width of the casing II so that with the sides of the casing in their normal condition, it would be impossible to insert the panel in the notches due tothe extensions 61 which are too wide to pass by the overhanging lip 68 of the notches I8. In order to mount the panel on the casing, it is necessary first to insert one pair of extensions 61 into` their respective notches from the sides beneath the lip 88 and then spring the other side of the casing outwardly and insert the extensions 61 into their respective notches below the lips 68. After the extensions 61 have been moved to the bottom of the notches, the side of the casing may be allowed to spring back, at which time the panel will be held in position due to the fact that the lips 58 will be engaged over the extensions 61 of the panel 63. A notch S6 is cut in each panel to accommodate a screw driver or other suitable tool for the purpose of springing the side of the casing in order to remove or mount the panel on the casing.

It will be readily seen that this method of mounting the panel is a simple and easy one because it is necessary only to spring the side of the casing slightly in order to snap the panel into place and yet after it is once in the proper` position there is no danger of it dropping out due to the fact that it is securely latched in by the overhanging lips on the notches.

In Figures l and 2, there is illustrated a cover 1I for the switch casing. This cover is provided with a slot at its top through which are inserted the top of the scale plate 58 and the indicating arm 54 and by means of which the top of the cover is held in position. The bottom part of the cover is provided with a latch 12 which is shown perhaps to better advantage in Figure 8. This latch comprises a leaf spring 13, one end of which is riveted to the side of the cover as shown at 14 and the free end of which carries a tapered catch 15. The narrow end of the catch faces the back I2 of the casing II so that as the cover is slipped into position the inside of the casing cams the catch inwardly and it slides along the casing until it drops into the hole I9. Due to the fact that the catch 15 has a straight faced edge 16 which engages the edge of the hole I9, the cover will be held in position because the spring 13 will maintain the catch in the hole I3. A manual release button 11 is attached to the spring 13 and extends through a hole 18 in the side of the cover 1I so that when it is desired to remove the cover the button 11 may be depressed moving the spring 13 and catch 15 inwardly, as viewed in Figure 8, to release the catch from the hole I9, at which time the bottom part of the cover may be pulled outwardly and then raised to withdraw it from around the scale plate 58 and the indicating arm 54. It may be pointed out that the bottom part of the cover has a cut-away portion to accommodate the conductors passing through the hole 2| in the bottom part of the casing through which they pass to connect with the terminals 66 on the panel board 63.

It is now believed that the operation of this device should be clear. For any variation in temperature, the thermostat 36 will cause the rod 38 to rotate and carry with it the mercury switch t in the switch casing just described and operate aangaat;

member 49 on the end of the rod 88. As has been explained above, the indicating arm I4 may be moved back and forth to rotate tube 92 which carries with it the thermostat 98 and which therefore adjusts the temperature at which the thermostat will actuate the switch. In order to properly calibrate 'the indicating arm, the screw l56 is loosened to change the position of the arm 54 with respect to the platelll.

It is possible to mount a different type of switch it from the same thermostat, and one way of do-I ing this has been illustrated in Figures 10 and 11. In this case, a slightly larger type of'panel has been used as shown at 88, which carries on its reverse side two brackets 8| and 82 which carry. respectively, two adjustable contact screws 89 and 84. Pivoted to the back of the panel 89 is a carrying member 85 onwhich are mounted two resilient arms 88 and 81 on which are mounted respectively two movable contacts 88 and 89 which cooperate with the stationary contacts 88 and 84. An arm 98 of the carrying member 85 is provided lwith a pin 9| which engages in an irregular slot 92 of a cam member 93. 'I'his cam member is carried by a mounting member 94 which is adjustably positioned on rod 98 by means of screw 95 in exactly the same manner as the mounting member 49 of the iirst modification.

Mounted on the front face' of the panel 88 are a series of terminals 96 for connecting the two switches into the proper control circuits. The remaining structure of this modification is identical with that of the first modification and therefore need not be described again.

On changes in temperature. the cam 93 will beI rotated, which rotation will have no effect upon the switch members 88 and'81 until the pin 9| reaches the steep slope in the slot 92, at which time the pin 9| will move the switch members either up or down, depending upon the direction of rotation of the cam 93 which will open or close the two switches.

This arrangement has the advantage that the panel 80 and the switch carrier along with its operating pin 9| may be removed as a unit from the switch casing in the same manner that the panel 83 is removed thereby making it very easy to replace the switches in the field and send the units back to the factory for repair. It is also possible to. substitute cams having different shaped slots for the cam 93 illustrated whereby many different types of switch operation may be obtained.

It will be seen, therefore, that I have provided a switch casing which may be very cheaply made and easily formed and which has therein an easy means for mounting on the casing a panel for terminal connections or a panel unit which carries an open contact switch. It will be seen further that there is also formed in this casing member a support for a scale plate which functions to indicate the temperature setting of the switch and which also helps to hold the cover in position and which has a hole near' the bottom which cooperates with a latch on the cover to hold the lower part in position. f

As certain changes and modifications of this invention may occur to those who are skilled in the art, I wish it to be distinctly understood that I am not to be limited by either of tLe modifications disclosed-but that the limits of my inven- -tion are to be determined by the scope of the appended claims.

I claim as my invention:

1. A switch casing comprising a back plate having rounded corners, four sides for said casing formed integrally with and bent up from said back plate, the ends of said sides being severed from said base and bent in to meet each other and conform to the shape of the rounded corfners of said base, said rounded corners of said base being bent in to closeup any gap which might be present between such corners and the ends of the sides, notches cut in two opposite sides of said casing, and an insulated panel supported in said notches.

2. A switch casing comprising a back plate having rounded corners, four sides for said casing formed integrally with and bent up from said back plate, the ends oi.\ said sides being severed from said base and bent in to meet each other and conform to the shape of the rounded corners of said base, said rounded corners of said base being bent in to close up any'gap which might be present between such corners and the ends of the sides, notches cut in two opposite sides of said casing, a short overhanging lip in each notch, and an insulated panel having extensions adapted'to t in said notches under said lips.

3. A switch casing comprising a* back plate having rounded corners, four sides for said casing formed integral1y with and bent up from said back plate, the ends of. said sides being severed from said base and bent in to meet each other and conform to the shape of the rounded corners of said base, said rounded corners of said base being bent in to close up any gap which might be present between such corners and the ends of the sides, notches -cut in two opposite sides of said casing, one outside corner 0f each notch having an overhanging lip, an insulated panel having extensions, said extensions being adapted to fit into said notches, the 'end of each extension being of such a width that it can not pass between the lip and side of a notch, but must bel inserted beneath said lip, and a notch cut in the insulated panel to facilitate bending the side of the casing slightly to insert and re move the insulated panel from the notches in the casing.

4. A switch casing comprising a back plate having rounded corners, four sides for said casing formed integrally with and bent up from said back plate, the ends of said sides being severed from said base and bent in to meet each other and conform to the shape of the rounded corners of said base, said rounded corners of said base being bent in to close up any gap which might be present between such corners and the ends of the sides, notches cut in two opposite sides of said casing, an insulated panel supported in said notches, a switch supported in said casing, condition responsive means to actuate said switch,

terminals on said panel, conductors connecting said switch to said terminals, and additional terminals on said panel for connection with an outside circuit.

5. A switch casing comprising a back plate having rounded corners, four sides for said casing formed integrally with and bent up from said baci platefthe ends of said sides being severedv notches, a switch supported on said panel, a condition responsive means for actuating said switch, and terminals on said panel for connection with a circuit to be controlled by said switch.

6. A switch casing having a back and sides, notches in opposite sides of said casing, a panel supported in said notches, a flexible switch arm, a switch carrier, said switch arm being carried by said switch carrier, means for pivotally supporting said switch carrier on said panel between said panel and theback of said switch casing, a stationary contact mounted on said panel for cooperation with said switch arm, a thermostat, a cam operated by said'therrnostat, an irregular slot in said cam, and a pin on said switch carrier extending through the slot in the cam.

7. A switch casing having sides, a switchin said casing, condition responsive means for actuating said switch, notches in opposite sides of said casing, at least one of said notches having an overhanging lip, an insulated panel having extensions thereon adapted to fit into said notches, the end of each extension which cooperates with a notch having an overhanging lip being of such a width that it will not pass between the lip and .the other side of the notch, whereby said extension may be put into place by bending the side of the casing slightly outwardly, and means electrically connecting the switch with said panel.

8. A switch casing having sides, notches in opposite sides of said casing, at least one of said notches having an overhanging lip, an insulated panel having extensions thereon adapted to t into said notches, the end of each extension which cooperates with a notch having an overhanging lip being of such a width that it will not pass between the lip and the other side of the notch, whereby said extension Amay be put into place by bending the side of the casing slightly outwardly, a. exible switch arm, a switch carrier, said switch arm being carried by said switch carrier, means for pivotally supporting said switch carrier on said panel between said panel and the back of said switch casing, -a stationary contact mounted on said panel for cooperation with said switch arm, a thermostat, a cam operated by said thermostat, and means connecting said switch carrier with said cam for operation thereby.

9. A switch casing comprising a back plate havlng rounded corners, four sides ior said casing formed integrally with and bent up from said back plate, the ends o! said sides being severed from said base and bent in to meet each other end to end and conform to the shape of the rounded corners of said base, a portion of said base including said rounded corners being bent in to close up any gap which might be present between such corners and the ends of the sides, a hole in one side -of said casing, a cover for the open end of said casing, and releasable means on said cover for engaging in said hole to maintain said cover on said casing.

10. A switch casing comprising a back and four sides, a switch mounted in said casing, condition responsive means for actuating said switch, means for adjusting said condition responsive means comprising an adjusting arm projecting from said casing, a hole in one side of said casing, a cover for closing the open end of said casing, and means to hold said cover on said casing including a slot through which the projecting portion of said adjusting arm is inserted, and releasable means on said cover for engagement with said hole.

11'. A switch casing comprising aback and four sides, a switch mounted in said casing, thermal responsive means for actuating said switch, an adjusting arm for said thermal responsive means part of which extends upwardly above said casing from the forward part thereof, a scale plate attached to the upper end of said casing and extending upwardly 4therefrom for cooperation with said adjusting arm, a hole in one of said sides at a substantial distance from said scale plate, a cover for'said casing; a slot in said cover through which the scale plate and adjusting arm are inserted so as to be visible from outside said casing when the cover is in place, a resilient member iixed at one end to the inside of said cover, a latch fixed to the free end of said member and normally lying against said cover but adapted to be cammed away by the side of said casing as said cover is placed thereon. said latch engaging said hole to hold said cover on after it has been moved to the proper position, and means extending through said cover for releasing said latch when it is desired to remove said cover from the casing.

BERTRAM P. POND. 

